Chemical mechanical polishing (CMP) is generally known in the art. For example U.S. Pat. No. 5,177,908 issued to Tuttle in 1993 describes a finishing element for semiconductor wafers, having a face shaped to provide a constant, or nearly constant, surface contact rate to a workpiece such as a semiconductor wafer in order to effect improved planarity of the workpiece. U.S. Pat. No. 5,234,867 to Schultz et al. issued in 1993 describes an apparatus for planarizing semiconductor wafers which in a preferred form includes a rotatable platen for polishing a surface of the semiconductor wafer and a motor for rotating the platen and a non-circular pad is mounted atop the platen to engage and polish the surface of the semiconductor wafer. Fixed abrasive finishing elements are known for polishing. Illustrative examples include U.S. Pat. No. 4,966,245 to Callinan, U.S. Pat. No. 5,823,855 to Robinson, and WO 98/06541 to Rutherford.
An objective of polishing of semiconductor layers is to make the semiconductor layers as nearly perfect as possible.
Current finishing elements and equipment can suffer from being costly to manufacture. Generally very complex mechanical equipment used when finishing semiconductor wafers. Complex, expensive, and bulky mechanical drives are generally used for generating polishing pad and wafer polishing motions. Also current finishing elements for semiconductor wafers generally have coextensive surface layers which can limit their versatility in some demanding finishing applications. Current polishing pads are generally larger than the workpiece being finished which consumes precious floor space in a semiconductor fab. Still further, current finishing apparatus are not capable of supplying a parallel finishing motion to finishing elements solely through magnetic coupling forces. Still further, current finishing apparatus are not capable of supplying multiple different parallel finishing motions to multiple finishing elements solely through magnetic coupling forces. Still further, current finishing apparatus are not capable of supplying multiple different parallel finishing motions to multiple different finishing elements solely through magnetic coupling forces. Still further, a lack of the above characteristics in a finishing element reduces the versatility of the finishing method which can be employed for semiconductor wafer surface finishing. Still further, current finishing pads can be limited in the way they apply pressure to the abrasives and in turn against the semiconductor wafer surface being finished. These unwanted effects are particularly important and can be deleterious to yield and cost of manufacture when manufacturing electronic wafers which require extremely close tolerances in required planarity and feature sizes.
It is an advantage of this invention to improve the finishing method for semiconductor wafer. surfaces to make them as perfect as possible. It is an advantage of this invention to make finishing elements and equipment with a lower cost of manufacture and reduce the mechanical complexity of the finishing equipment and thus also reduce the cost of finishing a semiconductor wafer surface. It is a preferred advantage of this invention to develop finishing apparatus and finishing elements that can be smaller than the workpiece being finished. It is further an advantage of the invention to develop finishing apparatus that are capable of supplying a parallel finishing motion to finishing elements solely through magnetic coupling forces. It is further an advantage of the invention to develop current finishing apparatus that are capable of supplying multiple different parallel finishing motions to multiple different finishing elements solely through magnetic coupling forces. It is an advantage of the invention to develop a finishing element which has a unique way of applying pressure to the unitary and/or a plurality of discrete finishing surface(s) and to the workpiece surface being finished. It is further an advantage of this invention to help improve yield and lower the cost of manufacture for finishing of workpieces having extremely close tolerances such as semiconductor wafers.
A preferred embodiment of this invention is directed to a method for finishing a semiconductor wafer surface comprising a step 1) of providing a magnetically responsive finishing element free of a nonmagnetic driving mechanism; a step 2) of providing a magnetic driving element operatively connected to a driving mechanism; a step 3) of providing a semiconductor wafer surface between the magnetically responsive finishing element and the magnetic driving element; a step 4) of magnetically coupling the magnetically responsive finishing element with the magnetic driving element; and a step 5) of applying an parallel operative finishing motion in the operative finishing interface formed between the semiconductor wafer surface and the magnetically responsive finishing element by moving magnetic driving element with the driving mechanism.
A preferred embodiment of this invention is directed to a method for finishing a semiconductor wafer surface comprising a step 1 of providing a plurality of magnetically responsive finishing elements free of any physically connected movement mechanism; a step 2) of providing a plurality of magnetic driving elements operatively connected to at least one driving mechanism; a step 3) of providing a semiconductor wafer surface between the plurality of magnetically responsive finishing elements and the plurality of the magnetic driving elements; a step 4) of magnetically coupling the magnetically responsive finishing elements with the plurality of the magnetic driving elements; and a step 6) of applying an parallel operative finishing motion in the operative finishing interface formed between the semiconductor wafer surface and the plurality of the magnetically responsive finishing elements by moving the plurality of the magnetic driving elements with at least one driving mechanism.
A preferred embodiment of this invention is directed to a method of removing unwanted material from a semiconductor wafer surface comprising a step 1) of providing a magnetically responsive finishing element having a finishing surface free of any physically connected movement mechanism; a step 2) of providing a magnetic driving element having a driving mechanism; a step 3) of positioning the semiconductor wafer being finished with a holder proximate to the magnetically responsive finishing element and between the magnetically responsive finishing element and magnetic driving element; a step 4) of applying an operative finishing motion comprising a magnetically induced parallel operative finishing motion in the interface between the semiconductor wafer surface being finished and the finishing surface of the magnetically responsive finishing element in order to remove the unwanted material.
A preferred embodiment of this invention is directed to a method of finishing a semiconductor wafer having a finishing cycle time comprising a step 1) of providing a plurality of magnetically responsive finishing elements having a finishing surface free of any nonmagnetic driving mechanism; a step 2) of providing a plurality of magnetic driving elements having at least one driving mechanism; a step 3) of providing a control subsystem having at least one semiconductor wafer finishing sensor for providing finishing information; a step 4) of positioning the semiconductor wafer being finished with a holder proximate to the plurality of the magnetic finishing elements and between the magnetically responsive finishing element and the plurality of the magnetic driving elements; a step 5) of applying an operative finishing motion comprising a magnetically induced parallel finishing motion between the semiconductor wafer surface being finished and the finishing surfaces of the plurality of the magnetically responsive finishing elements; and a step 6) of controlling in situ a control parameter with the finishing control subsystem after evaluating the finishing information.
A preferred embodiment of this invention is directed to an apparatus for finishing a semiconductor wafer surface comprising a plurality of magnetically responsive finishing elements free of any nonmagnetic driving mechanism; a magnetic driving means spaced apart from the plurality of the magnetically responsive finishing elements; a holder for a semiconductor wafer which exposes the semiconductor wafer surface for finishing, the holder situated between the plurality of the magnetically responsive finishing elements and the magnetic driving means, and wherein the magnetic driving means is for driving the plurality of the magnetically responsive finishing elements in an parallel operative finishing motion against the semiconductor wafer surface being finished.
A preferred embodiment of this invention is directed to an apparatus for finishing a semiconductor wafer surface comprising a magnetically responsive finishing element free of any nonmagnetic driving mechanism; a magnetic driving element operatively connected to a driving mechanism and wherein the magnetic driving element is spaced apart from the magnetically responsive finishing element; and a holder for a semiconductor wafer which exposes the semiconductor wafer surface for finishing, the holder situated between the magnetically responsive finishing element and the magnetic driving element and having an adjustable retainer ring.
A preferred embodiment of this invention is directed to an apparatus for finishing a semiconductor wafer surface comprising a plurality of magnetically responsive finishing elements free of any physically connected movement mechanism; a plurality of magnetic driving elements operatively connected to at least one driving mechanism and wherein the plurality of the magnetic driving elements is spaced apart from the magnetically responsive finishing element; a holder for a semiconductor wafer which exposes the semiconductor wafer surface for finishing to the plurality of the magnetically responsive finishing element, the holder situated between the plurality of the magnetically responsive finishing elements and the at least one magnetic driving element; and a finishing control subsystem having an operative semiconductor wafer sensor and magnetically responsive finishing element sensor.
A preferred embodiment of this invention is directed to a magnetic finishing element having a plurality of discrete finishing members for finishing a semiconductor wafer comprising a plurality discrete finishing members wherein each discrete finishing member has a surface area of less than the surface area of the semiconductor wafer being finished, each discrete finishing member has an abrasive finishing surface and a finishing member body, and a ratio of the shortest distance across in centimeters of the discrete finishing member body to the thickness in centimeters of each discrete finishing member body is at least 10/1; and at least one magnetic composite member has a corrosion resistant coating and the plurality of discrete finishing members is attached to the magnetic composite member.
A preferred embodiment of this invention is directed to a magnetic finishing element having a finishing layer with a finishing surface for finishing a semiconductor wafer comprising the finishing surface layer having a finishing surface area of less than the surface area of the semiconductor wafer being finished; and a magnetic composite member wherein the magnetic composite member is attached to the finishing surface layer and the magnetic composite member is protected with a polymeric corrosion protecting layer.
A preferred embodiment of this invention is directed to a magnetic finishing element having a finishing layer with finishing surface for finishing a semiconductor wafer comprising the finishing surface layer having a finishing surface area of less than the surface area of the semiconductor wafer being finished and a ratio of the shortest distance across in centimeters of the finishing surface layer to the thickness in centimeters of the finishing layer is at least 10/1, and a magnetic member wherein the magnetic composite member is attached directly or indirectly to the finishing surface layer.
Other preferred embodiments of my invention are described herein.
These and other advantages of the invention will become readily apparent to those of ordinary skill in the art after reading the following disclosure of the invention.